Its what they recommended with the grain bill so thats what I bought. I dont think it matters what belgian-yeast I choose - I asked the question as many belgians - tripel, dubbel and golden strong ales - all seem to follow a similar ferm temp guidance and the strains out there seem to show lower ideal temps. I know the yeasts can tolerate higher temps, but I was guessing over pitching would be the advice, to compensate for the higher temps and possible reduced effectiveness....

A lot of those recipes are duplicating what they read about Belgian brewing practices which might apply to a large facility but does not translate precisely to homebrewing scale or equipment. A lot of those recipes also intend for you to ramp up the temperatures from the 60s to the 80s rather than just starting there.

Yeast manufacturers give recommended ranges where the yeast will perform adequately and not throw off flavors if given typical wort conditions. That does not mean you cannot ferment outside that range or that under atypical wort conditions you cannot produce off flavors.

Also keep in mind you started this saying it calls for a slow ramp up to 80F. The majority of your fermentation will likely be done long before you get close to 80F. The higher temp at the end is probably there to give the yeast an environment it can finish its work in and produce some of the flavors that are expected in the type of beer.